Working on my 67 Cutlass. I installed a set of electric autometer auxiliary gauges and tach. I tapped into the gray wire that feeds the light that illuminates the heater controls. I realized this weekend that when I press the brake pedal the gauges will illuminate. Anyone have a recommendation on what I should be looking for? Thanks for any insight.

 

Do the gauge lights come on with the panel lights and do the panel lights come on when the brake pedal is depressed? The gray wire is supposed to be instrument panel lights.

 

The heater control panel light now comes on too.

 

It might not be a gray wire that you tapped in to. Double check your connections.

 

If you don't have a test light, get one. I have had one for years and could not do without it. Then you can find the right wire to tap into (should be gray).

 

Have you replaced any parking light or brake light bulbs lately? If you replace an 1157 (2 filiment/contact bulb) with an 1156 (single filiment/contact) bulb it will short the brake light circuit into the parking light circuit and "turn on" the dash lights when you step on the brake pedal. This can also happen if the 1157 bulb is installed wrong. Anything that can short the two seperate contacts inside the brake light/parking light socket will do this.

 

Winner winner chicken dinner. I had a burnt out brake light on Sunday so I through in a 1156 in since that was all I had and I wanted to take a quick road test...... Never thought that would cause this problem.... Thank you for saving me hours on agonizing pain chasing my tail under the dash...

 

That makes sense, never thought of that as a consideration.

 

I installed stereos for a living for 15 years. I can't tell you how many times I had to fix that because some knuckle draggin', cousin lovin', redneck put the wrong bulb in his Trans-Am and then blamed the stereo shop for his dash lights coming on when he stepped on the brakes. That was second only to the cigarette lighter unscrewing and blowing the fuse which caused the stereo to lose clock and preset memory and of course the cig lighter to not work.